SwRI-proposed Mission Could Encounter And Explore A Future Interstellar Comet Like3I/ATLAS Up Close

Southwest Research Institute (SwRI) has completed a mission study detailing how a proposed spacecraft could fly by an interstellar comet, providing remarkable insights into the properties of bodies originating beyond our solar system. The internally funded SwRI project developed the mission design, scientific objectives, payload and key requirements based on previous interstellar object (ISO) detections. Using the recent discovery of 3I/ATLAS, the team validated the mission concept, determining that 31/ATLAS could have been intercepted and observed by the proposed spacecraft.

In 2017, the object designated 1I/‘Oumuamua became the first interstellar comet (ISC) detected in the solar system. Its identification and naming nomenclature starts with the number 1, because it’s the first such object to be discovered, followed by an “I” for interstellar, and “ʻOumuamua,” which is the object’s given name — a Hawaiian word meaning “a messenger from afar arriving first.”

Its discovery was soon followed by the discovery of the second interstellar comet, ISC 2I/Borisov in 2019, and now this year, ISC 3I/ATLAS, which made worldwide headlines as it became the third officially recognized interstellar object to cross into our solar system. As new astronomical facilities like the National Science Foundation’s Vera Rubin Observatory develop new surveys and those capabilities expand, astronomers expect to discover many more ISCs over the next decade.

“These new kinds of objects offer humankind the first feasible opportunity to closely explore bodies formed in other star systems,” said SwRI Associate Vice President Dr. Alan Stern, a planetary scientist who led the study project. “An ISC flyby could give unprecedented insights into the composition, structure and properties of these objects, and it would significantly expand our understanding of solid body formation processes in other star systems.”

Upper left panel: Comet 3I/ATLAS as observed soon after its discovery. Upper right panel: Halley’s comet’s solid body as viewed up close by ESA’s Giotto spacecraft. Lower panel: The path of comet 3I/Atlas relative to the planets Mercury through Saturn and the SwRI mission interceptor study trajectory if the mission were to be launched this year. The red arc in the bottom panel is the mission trajectory from Earth to interstellar comet 3I/ATLAS. — Credit: NASA/ESA/UCLA/MPS

Scientists estimate that numerous interstellar objects of extrasolar origin pass inside Earth’s orbit each year, and that as many as 10,000 pass inside the Neptune’s orbit in any given year. The SwRI-led internal research study tackled the unique design challenges and defined the costs and payload needs associated with an ISC mission. The mission concept could be later proposed to NASA. The hyperbolic trajectories and high velocities of these objects preclude orbiting them with current technology, but the SwRI study showed that flyby reconnaissance is feasible and affordable.

“The trajectory of 3I/ATLAS is within the interceptable range of the mission we designed, and the scientific observations made during such a flyby would be groundbreaking,” said SwRI’s Matthew Freeman, the study’s project manager.” The proposed mission would be a high-speed, head-on flyby that would collect a large amount of valuable data and could also serve as a model for future missions to other ISCs.”

SwRI scientists and their external collaborators in the study established the major, comprehensive scientific objectives for a mission to an ISC. Determining the physical properties of the body would offer insights to its formation and evolution. Examining the ISC composition could help explain its origins and interpret how evolutionary forces have affected the comet since its formation. Yet another objective is to thoroughly investigate the nature of the object’s coma, the escaping atmosphere emanating from its central body.

To develop mission trajectory options, SwRI developed software that generated a representative, synthetic population of ISCs then calculated a minimum energy trajectory from Earth to the path of each comet. The software’s calculations showed that a low-energy rendezvous trajectory is possible, and in many cases would require less launch and in-flight velocity change resources than many other solar system missions. SwRI orbital mechanics expert, Dr. Mark Tapley, used this software to calculate the trajectory that the proposed spacecraft could have taken from Earth to intercept 3I/ATLAS. He found that the mission designed by SwRI’s study could have reached 3I/ATLAS.

“The very encouraging thing about the appearance of 3I/ATLAS is that it further strengthens the case that our study for an ISC mission made,” said Tapley. “We demonstrated that it doesn’t take anything harder than the technologies and launch performance like missions that NASA has already flown to encounter these interstellar comets.”

About SwRI:
SwRI is an independent, nonprofit, applied research and development organization based in San Antonio, Texas, with more than 3,200 employees and an annual research volume of $915 million. Southwest Research Institute and SwRI are registered marks in the U.S. Patent and Trademark Office. For more information, please visit www.swri.org.

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